This format of light switch has three discreet switches on a single face plate. Basically this is three Single gang 2 way switches on a single face plate.

Triple gang switch face

Fig 2: Triple gang 2 way light switch

Switch mechanism

Fig 3: Two way light switch mechanism

Each of the gangs (or switches) above in Fig 2 (of which there are three) work like this (Fig 3): In position 1 (when the switch is down or ‘on’), COM and L1 are connected together (just like the one way switch). In position 2 (when the switch is up or ‘off’), COM and L2 are connected together.

There are no connections between the three gangs in Fig 2. Each gang is a single discreet switch.